


Adventures in Onanism

by doodledinmypants



Category: Supernatural
Genre: Anal Sex, Angst, Grumpy!Cas, Humor, M/M, Masturbation, VERY brief mention of Sam/OFC (off-screen), Voyeurism, aggressive!Cas, conveniently absent!Sam, fallen!cas, human!Cas, molestation of fruit (not serious food kink though), nocturnal emissions
Language: English
Status: Completed
Published: 2013-09-07
Updated: 2013-09-07
Packaged: 2017-12-25 21:23:54
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,067
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/957748
Author URL: https://archiveofourown.org/users/doodledinmypants/pseuds/doodledinmypants
Summary: <blockquote class="userstuff">
              <p>As Castiel grows increasingly more human, with human needs, Dean appoints himself Castiel's personal guide to mortal living.  It's all fun and games, until it gets awkward.  And then fun again.</p>
            </blockquote>





	Adventures in Onanism

**Author's Note:**

> **Spoilers:** Maybe some general for season 5 if you squint, but nothing episode-specific, really. This fic sort of exists in its own bubble, though I wouldn't go so far as to call it AU.  
>  Originally posted on [](http://deancastiel.livejournal.com/profile)[](http://deancastiel.livejournal.com/)**deancastiel**.

It happened in steps. Dean thought he should start keeping notes of the little milestones, the ways in which Castiel was shuffling ever closer to humanity, but it seemed cruel to even acknowledge these things. Castiel had chosen Dean over Heaven, and was losing his Grace for it. Not ripped out, as Anna's was, but bleeding out slowly, like a deep wound.

First, he lost his ability to heal others. Then, his ability to exorcise demons with a touch. When he finally lost the gift of flight, Dean offered him a place in the back seat of the Impala, which the angel had accepted with silent thanks.

He began eating, which thrilled Dean to no end (he made lists sometimes, when he couldn't sleep, of things he wanted Cas to try next), and which inevitably led to the awkwardness of learning to use a toilet. Showering and other personal hygiene rituals followed shortly thereafter, including laundry and changing into clean clothing (they wound up buying him some new sets of clothes, since even Dean's pants were too big on him, and there was no way he was sharing underwear). Castiel was a quick study; he knew how these things worked in theory, though he seemed vaguely horrified and offended that he was now reduced to such base functions himself.

When he began dozing off in the car on long stretches of highway, Dean decided it was time the angel start sleeping in a proper bed.

And that was where things got awkward.

Motel rooms, as a general rule, didn't come with three beds. That either meant getting a second room, or sleeping double in one of the beds (or obtaining a cot, but motel cots were notoriously unreliable, when one was even available). Since getting another room wasn't cost effective, and Sam was too ginormous to share a bed even with his own gangly limbs, it came down to Dean bunking with Castiel. Which, really, he didn't have a problem doing. Cas was a lot smaller than he looked once he was out of that trench coat (and he did take it off now, once in awhile, though he still wore it outside of their motel rooms more often than not-- Dean thought it must be like armor, or maybe a security blanket), and he curled into an even smaller shape when he slept, so it wasn't like he hogged the bed or anything.

No, the problem was slightly more embarrassing than that. Dean knew that Castiel was new to his body's functions and reactions (or rather, Jimmy's, but it looked as though Cas was taking up permanent residence in the poor guy's meat and there wasn't much anyone could do about it), but it still caused him a moment of panic when he woke up with something hard nestled against his ass in the morning.

“Dude,” Dean grumbled, rolling away after elbowing Castiel, who had apparently decided to spoon him at some point. “You need to learn to take care of that.” He was just glad that Sam had already gotten up and left to fetch breakfast, so that he wasn't here to witness this.

“I don't see the point,” Cas grouched back, hair messier than usual and flattened along one side from the pillow. “If I ignore it, it goes away on its own. Apologies for... invading your space.”

“Are you saying you've never...” Dean started, but the look on Castiel's face was answer enough. “Aw, man. If you don't clean the pipes once in awhile, you're gonna wind up with something more embarrassing than morning wood, Cas.”

The angel's eyes narrowed. “It's not necessary, Dean,” he growled in that tone that meant, 'I don't have time for this stupid human shit, so just drop it.' He hadn't been coping with the 'burgeoning humanity' thing very well. Oh, sure, he caught on to the mechanics of it easily enough, but the brothers Winchester had been dealing with the fallout, mostly in the form of Castiel's Really Bad Moods. If Castiel the angel had seemed impatient, stubborn, and brusque, it was nothing compared to Cas the almost-but-not-quite-human. Fortunately, Dean had discovered that Cas was a whole lot more tractable after coffee.

Unfortunately, he hadn't had any coffee yet. This conversation wasn't going to go anywhere until the angel had gotten his caffeine fix, and Dean knew it, so he just shrugged and got up to use the shower.

…

That very next night, Dean's ominous prediction came true. Castiel woke up in the wee hours of the morning, gasping and whimpering. There was a sticky, cooling dampness in his shorts, and he groaned when he realized what it was. As quietly as he could, he snuck into the bathroom to clean himself and change into fresh underwear. He gritted his teeth, resolving not to tell Dean about this new development-- however, when he returned to the bed, he found the hunter staring up at him with a knowing expression.

“Interesting dreams?” Dean inquired casually, but his eyebrow was doing that thing that almost always precipitated a full-on smirk. Castiel glared at him, climbed back into his side of the bed, and pointedly turned his back on the other man. They didn't speak again until morning.

…

“It's nothing to be ashamed of, and it's not like it'll take up any extra time out of your day,” Dean told him over breakfast. Sam had already finished his and wandered off to the library for research, thankfully. “Just rub one off in the shower. It's simple maintenance.”

“I don't understand why you keep insisting that I engage in onanism, Dean,” rumbled the angel into his styrofoam coffee cup. “I eat, breathe, sleep, and expel waste as this body requires. Ignoring these... superfluous reactions will not cause it harm. There are more important matters of concern.” He raised an eyebrow at Dean, and the unspoken, 'like the Apocalypse' made Dean roll his eyes.

“And I don't understand why you're being such a prude about this. Ignoring it only makes it worse, as you've already figured out on your own.” He looked a little smug at that. Cas wanted to hit him.

“Even if I wanted to, I don't...” Castiel's mouth snapped shut. He stared fixedly at the sludge in the bottom of his coffee cup.

“What? You don't what?” Dean's eyes lit with understanding. “You don't know how? Is that it?”

Castiel nodded, a tiny, barely perceptible motion.

Dean laughed, but it wasn't mocking. It sounded more like relief. “Dude, if that's all that's stopping you... Look, it's real simple. Just wrap your hand around it, like this.” He mimed with a banana, which Sam had brought in the vain hope that Dean might eat something healthy for breakfast.

“Dean, stop,” Cas cut him off with a groan, resting his face in his hands. “I'm not doing this. It's stupid. And you're molesting a fruit.”

Dean's mouth quirked into a grin. “Suit yourself.”

…

The next time Cas had a “nocturnal emission,” Dean didn't say anything. The same day, however, he dealt with it in typical Dean fashion: by shoving a stack of skin mags into the angel's hands and locking him in the bathroom (by jamming a chair under the doorknob) until Castiel pounded on the door and yelled to be let out. Sam finally did, when he got back, and the resulting demand for an explanation from Dean ensured that Cas wouldn't be bothered for awhile. He was stupidly grateful to the younger Winchester for that.

…

After a case involving a poltergeist in an elementary school and a really, really grateful (not to mention smoking hot) kindergarten teacher, Sam got his own room for the night. Dean had gone off to a bar to hustle pool and presumably find some tail himself. Castiel had declined to go with him, so he sat alone in the hotel room that he still shared with Dean, and wondered how he should entertain himself. He couldn't just fly around anymore, so his options were somewhat limited.

He flipped on the television and channel surfed for awhile, but such diversions had never held a lot of interest for him, so he turned it off again.

He drummed his fingers on the bedspread. Caught himself. Stopped.

He found a sticky quarter in the bottom of Dean's duffel bag and plunked it into the Magic Fingers box out of curiosity. When the bed began shuddering violently beneath him, he leapt off of it and watched it from across the room, warily, until it stopped.

He looked through the small collection of occult books and fiction novels the Winchesters had with them, but he'd already read them all at least twice. Some more than that. He turned to the only other reading material in the room (except for the Gideon bible, which he had read considerably more times than any of the other books, if only to shake his head at human fallibility and interpretation), which happened to be Busty Asian Beauties.

He was only going to see if it had any interesting articles, he told himself, opening the magazine to a random page and staring at the contents. It would figure that skin mags were designed to fall open easily at the centerfold. As Castiel gazed at the creased, glossy paper, he felt his body react in its crude, predictable way. With a groan of resignment, he unzipped his jeans and took himself in hand. At least he'd found a way to cure his boredom.

That was how Dean found him an hour later. The hunter had hustled pool a little too well, and had decided to quit while he was ahead (before any of the disgruntled bar patrons whose money he'd taken could realize there were more of them than him). Thus, he returned to the room with a fat wad of hard-won cash, only a couple of drinks in his system, and no company of the friendly female variety. That was all right, though. He could just hang out with...

“Cas?”

The angel froze. Dean froze. Castiel was sitting on the bed amidst a pile of open skin mags, pants bunched around his ankles, shirt unbuttoned and tie hanging loose around his shoulders (he still wore Jimmy's clothes whenever possible, claiming he felt most comfortable in them, and Dean would never admit that he found it kind of cute), and his cock jutting into the air above Cas' curled fingers, flushed and dark. He was breathing heavily, face blotchy and red, sweat matting the errant feathers of his hair to his forehead.

Dean cleared his throat. “Should I, uh, leave you two alone?” he quipped, but his voice came out dry and nervous. A tiny voice inside him cheered triumphantly. So, the angel had finally decided to take his advice. Awesome.

Castiel gave a frustrated groan and kicked off his pants the rest of the way, letting go of his erection and scrambling off the bed hastily. Dean thought he was going to retreat into the bathroom, but to his shock, the angel went straight for _him_. “Get over here,” he growled, fisting Dean's shirt front and dragging him back to the bed. Dean was too startled to fight back, and let Cas push him down until he was sitting on the bed. With a sweep of Cas' arm, all of the magazines fluttered noisily to the floor. Dean stared up at him, eyes wide and brow creased in bewilderment, and tried not to stare at his crotch.

“Uh, Cas? What...?” Dean began, but the angel cut him off abruptly.

“It isn't working!” Castiel railed. “I have stared at these images of nude women, and manipulated my penis in every manner I can imagine, but I cannot achieve climax!”

Dean squirmed. “Okay, first of all? You need to get some new vocabulary if we're gonna talk about this. Second, what do you want me to do about it?” Belatedly, he realized that this was probably not the sort of question he should be asking, as Castiel tended to take things very literally.

“You said you wanted to help me with this,” Cas pointed out impatiently. “Show me.”

Involuntarily, Dean's gaze slid down to Cas' erection. He licked his lips, but his mouth had suddenly gone dry. “Um...”

“I'm not asking you to do it for me.” And Dean hazarded a guess that Castiel must have learned that eye-roll from Sam. “However.... I think I may need that practical demonstration after all.” He pressed his lips into a thin line, gaze sliding away from Dean, obviously finding it difficult to swallow his pride enough to ask for such a thing.

Dean stood up then, which wasn't a great idea, either, because it put him right in Cas' personal space. He jumped back a little when he felt something poke him in the hip. “You're right, I did say I was gonna help you through this whole 'turning mortal' schtick. Just... sit down for a minute, would you?”

The hunter ran his fingers through his short hair and exhaled slowly, as Castiel obediently sat down on the bed where Dean had been. Right. Time to teach the angel how to jerk off. His life just never got less weird, did it? At least Sam was out of the picture for the night. He'd never live this down if his brother found out.

“So... what have you tried so far?” Dean asked, trying to keep his tone aloof and professional. It wasn't easy, as there was a half-naked, debauched angel on his bed. The fact that Castiel was inhabiting a male form didn't make much difference to Dean; sex was sex, and he'd done his share of experimentation over the years. “Show me.”

Castiel glared up at him, and Dean raised his hands, palms-out. “Work with me here, Cas.”

With a sigh, the angel took his slightly flagging erection in hand again and gave it a clinical stroke from root to tip. “I've done this, mostly. Differences in pressure and speed. Instead of... _getting off_ , however, I only seem to be irritating the flesh.”

Dean raised an eyebrow, but he did lean down to get a better look. Sure enough, Castiel's skin was a dry and angry red. So it hadn't just been the flush of arousal. “Well, there's your first problem. You need lubrication. Hold on.”

From his duffel bag, he produced a small bottle of KY and tossed it to Castiel, who caught it easily with his free hand. The angel stared at it with the same kind of penetrating focus he gave ancient texts, Enochian rituals, and Dean. “What do I do with this?”

“Do I have to spell it out for you? Come on, Cas, you're a smart angel. Use that nerdy brain of yours.” Dean just smirked at the scowl he received in return.

Flicking the cap open, Cas overturned the bottle and squeezed a small amount of the clear gel from it-- directly onto his cock. He gave a startled grunt, eyes popping wide, going rigid all over.

Dean couldn't help but laugh. “Yeah, genius. You warm it up in your hand first, normally. Guess I should've warned you.” But his unrepentant grin said otherwise. “Well? Get moving. It's not going to get any warmer if you just let it sit there.”

That squinty blue glare fixed on Dean, Castiel slowly began to move his hand again. Then, something in his expression changed, relaxed, and he made a soft, surprised sound in his throat. “It's... an improvement,” he admitted, stroking himself languidly, working the lubricant into his flesh until he was slick and wet.

Swallowing past the dryness in his throat, Dean nodded. “Good. You got this? Because I'm, uh, gonna go have a shower.”

Castiel tilted his head in that quizzical way he had (one of the few things he hadn't lost along with his Grace), and gave the hunter a canny look. “Are you going to 'rub one off', too?” he asked, with open curiosity.

Dean bit back a groan as his eyes drifted down of their own accord to the angel's lap. “That's not something you ask a guy, Cas,” he protested weakly.

“Show me.” He hadn't stopped touching himself, but he was going far too slowly for any kind of release. “I want to see how you do it.”

And that should _not_ have made Dean's cock jerk to full attention the way it did, but he found himself unbuckling his belt and dropping his jeans and shorts to the floor anyway. Sitting on the opposite bed, a scant few feet between them, he held out a hand. “Pass the lube.” Castiel obliged, not once taking his eyes off of Dean. He found that simultaneously a little creepy and hot as hell-- but that was nothing new.

Warming the gel in his palm first, he slicked himself up with a low, breathless moan. Castiel's hand stilled for a second as the angel focused all of his attention on what Dean was doing. Dean tried to ignore the staring, concentrating instead on demonstrating what a proper self-service hand job should look like. “You want a nice, firm grip, see? Then pull up like this, maybe twist a little at the end if you like that sort of thing... There you go. You've got it.” Castiel was matching him stroke for stroke, falling into Dean's rhythm as though he were on the other side of a mirror. It was, like most things dealing with Castiel, a little weird, but Dean could handle weird.

For a time, the only sound in the room was the wet slide of flesh on flesh, the harsh, heavy breathing of the two men, interspersed with the occasional grunt or moan. It was Castiel who broke the silence first.

“Dean,” he panted, face flushed and glistening with sweat again. “It's not enough. I need... I need something else.”

“What? You're kidding me,” Dean groaned. He was getting close already, more on the vision of Castiel jerking himself across from him than the friction of his own hand. “Do what you need to do, just let me... I'm almost...”

Dean's eyes drifted shut, which was probably why it startled him so badly when he suddenly found himself with a lap full of horny angel. “Cas! What the fuck?!”

“Dean,” moaned Castiel, and the low rumble of his voice went straight to the hunter's cock. He buried his face against the side of Dean's neck, hot, moist breath puffing against already damp skin. “I need you... inside me.”

“ _Fuck!_ ” Dean came undone with a shout, painting Cas' chest and stomach with hot splashes. Castiel stared down at him, first surprised, then unimpressed. “Don't give me that look. It's your own damn fault,” he said, voice gruff and shaky. “Can't just say shit like that to a guy...”

The angel got up from his lap and returned to the other bed, flopping down face-first with a low groan. “This is _pointless_ ,” came the muffled lament from his pillow. Dean rolled his eyes at the dramatics and fetched a warm, damp washcloth to clean himself. After rinsing it in warm water again, he brought it over to Cas and gently rolled the angel over to wash him as well, carefully avoiding his unsatisfied erection. Castiel stared blankly up at the ceiling throughout this process, as though refusing to acknowledge the other man.

“You could fuck me instead,” offered Dean, and that got Cas' attention. At least his dick's, if that interested little twitch was anything to go by. “If that's what it takes to get you off, then fine. I'm game.” He hadn't taken it like that in years, but he figured it was like riding a bicycle. Likely to skin your knees a few times, but you never really forgot how once you learned.

“... All right,” said Castiel finally. He raised himself on his elbows and gave Dean a considering look. “What do I need to do?”

“Just lie down. I'll handle it,” Dean assured him. He got the lube again and coated his fingers thoroughly, facing away from the angel in order to give him a better view and reaching back to prepare himself. Castiel watched, fascinated, as the first finger disappeared up to the second knuckle into Dean. The hunter added a second finger, grunting softly as he found the firm bump of his prostate. He didn't have the refractory period of a teenager anymore, but he knew it wouldn't take much more of that before he was hard again.

By the time he worked his way up to a third finger, fucking himself on his hand, Castiel was up on his knees behind him. Dean could feel him breathing, warm and wanting, against the back of his neck. “Dean,” he murmured, lips and teeth catching on the soft edge of his ear, sucking it sharply into the wet heat of his mouth. Dean moaned appreciatively, and Cas did it again, moving down to lick and bite at his neck. He wasn't gentle about it, but Dean liked that. Had always liked that about Cas, if he were being honest with himself.

“Ready,” Dean breathed, removing his fingers and searching behind him for Castiel. The angel was there, and he slicked his hand over Cas' cock with the remainder of the lube before guiding him closer. Cas took things the rest of the way, lining up and breaching him slowly. They gasped almost in tandem, and then Cas couldn't hold back any longer, thrusting in hard and fast.

“Oh, fuck yeah. So good, Cas,” groaned Dean, as the angel shoved him down against the mattress and fucked him relentlessly, hips slamming up against his ass like he wanted to break Dean. Maybe he would. He didn't really care. The burn and stretch of Castiel inside him hurt like hell, made his thighs shake, drew thready moans out of his raw throat, but he wouldn't-- couldn't-- tell the angel to stop. He was achingly hard again, leaking and wet against the scratchy, stale bedspread.

Wiry arms, thinner than his own but nearly as strong, wrapped around his torso and pulled him into an upright kneeling position. Castiel's thrusts weren't as deep from this angle, but they were quicker, and he was hitting that magic spot inside Dean with every pass. Dean uttered a strangled yell as he came for a second time without warning, his muscles clenching down hard around Cas and dragging the angel over the edge into his own orgasm. Castiel _growled_ , a sound that vibrated through Dean's spine, and bit down hard on the hunter's shoulder as he rode out the waves of his pleasure.

As if by unspoken agreement, they collapsed simultaneously onto the bed afterward, Dean narrowly avoiding his own wet spot on the comforter. Castiel slipped out of him, finally sated, and returned Dean's earlier favor by taking the damp washcloth (now cold, unfortunately) and cleaning them both with gentle efficiency. Dean shivered a little at the chilly contact but didn't complain.

When they'd both had a moment to catch their breath and absorb just what had happened between them, Dean stood up and pulled on his underwear and t-shirt, getting ready for bed. “I guess we'll have to work on that whole 'taking care of it yourself' part later,” he chuckled, voice gone rough and raw.

Castiel nodded, considering his words. “I... enjoyed this method,” he offered tentatively, his own voice gruffer than usual, eyebrows lifting a fraction. “If you're not opposed, maybe we could try it again?”

Dean gave him an appraising look, then nodded slowly. “Yeah.” He swallowed past the burr in his throat. “But, uh. We should switch it up a little. Try different things. Don't want you getting bored.”

Even without his Grace-given powers, the angel still had the uncanny ability to be right up in his personal space within an instant. Cas gave him that soul-deep stare from bare inches away, and it made Dean wonder briefly if his body would try to rally for a third round. “As long as it's with you, I doubt it will ever be boring,” Castiel told him, very seriously. Then, he pressed a kiss to Dean's mouth that was just as hot and demanding as the rest of him, and the hunter opened to him just as willingly.

...

End!  



End file.
